A preliminary assessment of mineral dust outbreaks in Italian coastal cities

The Mediterranean region, being the area well known for its predominantly mild climate, has been subject to human intervention for millennia. The fast population growth and its intense rural and transportation activities are the main responsible factors that contribute to increasing anthropogenic airborne pollutant emissions. In addition to anthropogenic emissions, the area is influenced also by natural emissions such as episodes of wind-blown mineral dust from the Sahara desert. In order to assess and speciate the growing emissions over the Mediterranean region, we used WRF-Chem chemical transport model. One-year modellings based on two distinct simulations, have been carried out: the first considering only mineral dust (‘DUSTONLY’ simulation) and the second one considering othertypes of emissions, such as biogenic and anthropogenic (‘MOZMOSAIC’ simulation). Both simulations use the Goddard Chemistry Aerosol Radiation and Transport dust emission scheme. The National Centers for Environmental Prediction (NCEP)/National Center for Atmospheric Research (NCAR) reanalysis data were used to assess the accuracy of simulated meteorological fields such as temperature, relative humidity and wind speed and direction, showing a great capability of WRF-Chem to model the experimental fields and their spatial trends. The comparison between the modelled dust column mass density and the same field calculated through the corresponding Modern-Era Retrospective Analysis for Research and Applications, version 2 (MERRA2) reanalysis showed an evident dust load overestimate over North Africa. Such overestimate is confirmed by the comparison of both simulations with the AERONET aerosol optical depth (AOD) (550 nm) products: Rome and Naples stations have nearly the same trend and AOD peaks are captured well, but the dust concentrations are overestimated from both simulations.